The goal of the Path Core is to accession and prepare well characterized tissue for analysis. This effort will be led by Dr. Noam Harpaz Chief of GI Pathology at the Mount Sinai Medical Center, and two GI pathologists. Both human and mouse components are served by the core. This core will be heavily used by all projects with the following aims: Specific Aim 1: To retrieve, process, and distribute suitable specimens for the four Projects as needed (human - projects 1 and 3;murine - projects 2, 3 and 4). Specific Aim 2: To stabilize and preserve undistributed tissues for long-term storage and make them available to other Projects or investigators as needed. Specific Aim 3: To maintain a detailed tissue database (mouse and human) documenting the anatomic sources, the gross and microscopic pathological characteristics of the individual tissue specimens, and the clinical and pathological data pertaining to the patients (or mice) from whom specimens were derived. . Specific Aim 4: To perform blinded histologic evaluation and scoring of inflammation in the different murine models of IBD used in projects 2, 3 and 4. (Dr. Xu).